Okay here it is. I bought a '48 cub that was refurbished and ran really well for about 3 hours collectively. When I try to start it it turns over and wants to start but doesn't . The carburator floods immediately. If I try enough times it eventually starts and runs well. But when I turn it off the same thing happens. Won't start. I bought a new carb , rebuilt it all that. The same problem occured. When I turn it off a strange whirring sound occurs that never happened when it was running normally. I'm far from an expert but everyone says carb ... but I not so sure. Also maybe some could explain how to use the idle screw and the other screw on the throttle lever. Very confused.... Thanks everyone... Byron in CT.

First of all - welcome to the forum! I suggest you do a full ignition tune-up or at least confirm that you have a good hot spark and that your timing is on.Are you using the choke to start? Most cubs don't tolerate a lot of choke. Generally a couple of revolutions with the choke on and then half-choke or none at all and they will start.It also would be good to do a compression test and valve adjustment to make sure things are where they're supposed to be.Check those basic items and most likely you will find your problem.

BigdogIf you can't fix it with a hammer, you've got an electrical problem.

Even though gas was coming out of my carb, like yours, I believe mine was an issue of carb and mag/distributor. I rebuilt the carb, verified the float height and the gas level in the carb, replaced the spark plug wires and ensured a spark at each plug, and checked the mag timing. I've got a distributor tune-up kit coming from TM because I had burn marks inside the distributor rotor cap.

G'day to you and my there sure seems to be a lot of no-start issues lately...

You have gotten a lot of good information (and some of us have learned something new as well) .. and I would suggest you follow the links below as there is a rather large amount of information/resources available to our members.

My 48 Cub Ellie has always made a little wheezing sound as she shuts down, never paid a lot of attention to it till now when I think I just got a clue as to what it was and it is kinda reassuring as well:

Bigdog wrote:Most of my cubs have a "wheezing" sound when shut off. Just a little noise when the engine rolls back from an incomplete compression cycle. The better the compression, the more noticeable it is.

I used to think it was partially connected to the last bit of fuel being consumed and then the last gasp of air. Now it makes sense that it is compression -- probably same thing -- BD just explained it better

Check if the "whirring" sound is coming from the radiator by removing the radiator cap while the noise is present. You said it was coming from the front. I suspect that pressure built up inside the radiator due to the water getting warm is escaping around the cap and making the noise. It's the same idea as when you hold a blade of grass between your thumbs and blow through it to make a very loud whistle.

If it's coming from the radiator, it's normal.

The gas pouring is too much choke and/or a sticking float. If you're NOT pulling the choke, it's a sticking float.

Carbs can be a little tricky if you're new to it. You never get it right on the first try. New ones get banged around during shipping and usually need to be adjusted right out of the box too...

Question about 6v batteries.... is it uncommon for 6v batteries to weaken overnight when it is very cold. And if I leave it hooked up to the charger overnight will the charger not continue to charge and harm the battery once the charge completes. Thanks. Byron in CT.

You can use a battery tender, they say they work well. It is hard to say on your 6 Volt battery too many variables, how old is the battery, how many cranking amps, and was it fully charged to start with.Boss